ABCs of z/OS System Programming Volume 3 - IBM Redbooks

4.27 Program objects in a PDSE
Functions to create, update, execute, and access
program objects in PDSEs
Load module format
Binder replaces linkage editor
Program fetch
DESERV internal interface function AMASPZAP
Set of utilities such as IEWTPORT, which builds
transportable programs from program objects and
vice versa
Coexistence between PDS and PDSE load module
libraries in the same system
Figure 4-37 Program objects in PDSE
Program objects in PDSE
Program objects are created automatically when load modules are copied into a PDSE.
Likewise, program objects are automatically converted back to load modules when they are
copied into a partitioned data set. Note that certain program objects cannot be converted into
load modules because they use features of program objects that do not exist in load modules.
A load module is an executable program loaded by the binder in a PDS. A program object is
an executable program loaded by the binder in a PDSE.
Load module format
For accessing a PDS directory or member, most PDSE interfaces are indistinguishable from
PDS interfaces. However, PDSEs have a different internal format, which gives them increased
usability. Each member name can be eight bytes long. The primary name for a program
object can be eight bytes long. Alias names for program objects can be up to 1024 bytes long.
The records of a given member of a PDSE are written or retrieved sequentially. You can use a
PDSE in place of a PDS to store data, or to store programs in the form of program objects. A
program object is similar to a load module in a PDS. A load module cannot reside in a PDSE
and be used as a load module. One PDSE cannot contain a mixture of program objects and
data members.
The binder
The binder is the program that processes the output of language translators and compilers
into an executable program (load module or program object). It replaced the linkage editor
152 ABCs of z/OS System Programming Volume 3